The following data refer to one year for Monroe Fabricators. Fill in the blanks. $ 7,800 Direct materials inventory, January 1 Direct materials inventory, December 31 Work-in-process inventory, January 1 Work-in-process inventory, December 31 Finished goods inventory, January 1 Finished goods inventory, December 31 Purchases of direct materials Cost of goods manufactured during the year Total manufacturing costs Cost of goods sold Gross margin Direct labor 8,100 11,400 5,700 900 48,300 163,350 168,150 147,750 Direct materials used 43,800 Manufacturing overhead 41,400 Sales revenue